The early detection and treatment of hearing impairment are becoming increasingly important components of pediatric care. The interest in early diagnosis is manifested by the emergence of many hearing screening programs for newborn infants, concern about the long-term effects of otitis media in infancy on language development and later learning problems, and problems that promote pediatrician's awareness of communication development. The goal of Phase II is to refine and complete development of a practical hearing test for infants through preschool-age based on Clinical VRA and PAC. This will be achieved through 1) development of durable, commercial quality hardware, 2) optimization of test algorithms through computer simulation and small scale clinical trials with infants, 3) optimization of software for accuracy and efficiency, and 4) large scale clinical tests at three sites; a) high risk infants who were screened with ABR in a newborn nursery, b) normal children in a pediatric practice, and c) children referred to an otolaryngology department of a large city hospital. In large scale trials, audiograms obtained with the device will be compared with other methods used with infants (e.g., ABR, immittance). In addition, the capabilities of the device will be expanded to include signal presentation through bone oscillator and earphones and to extend its use to older children via a button-push response.